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// unit-test: UninhabitedEnumBranching
enum Empty {}
// test matching an enum with uninhabited variants
enum Test1 {
A(Empty),
B(Empty),
C,
}
// test an enum where the discriminants don't match the variant indexes
// (the optimization should do nothing here)
enum Test2 {
D = 4,
E = 5,
}
// test matching an enum with uninhabited variants and multiple inhabited
enum Test3 {
A(Empty),
B(Empty),
C,
D,
}
struct Plop {
xx: u32,
test3: Test3,
}
// EMIT_MIR uninhabited_enum_branching.simple.UninhabitedEnumBranching.diff
fn simple() {
// CHECK-LABEL: fn simple(
// CHECK: [[discr:_.*]] = discriminant(
// CHECK: switchInt(move [[discr]]) -> [0: [[unreachable:bb.*]], 1: [[unreachable]], 2: bb1, otherwise: [[unreachable]]];
// CHECK: [[unreachable]]: {
// CHECK-NEXT: unreachable;
match Test1::C {
Test1::A(_) => "A(Empty)",
Test1::B(_) => "B(Empty)",
Test1::C => "C",
};
}
// EMIT_MIR uninhabited_enum_branching.custom_discriminant.UninhabitedEnumBranching.diff
fn custom_discriminant() {
// CHECK-LABEL: fn custom_discriminant(
// CHECK: [[discr:_.*]] = discriminant(
// CHECK: switchInt(move [[discr]]) -> [4: bb3, 5: bb1, otherwise: bb5];
// CHECK: bb5: {
// CHECK-NEXT: unreachable;
match Test2::D {
Test2::D => "D",
Test2::E => "E",
};
}
// EMIT_MIR uninhabited_enum_branching.byref.UninhabitedEnumBranching.diff
fn byref() {
// CHECK-LABEL: fn byref(
let plop = Plop { xx: 51, test3: Test3::C };
// CHECK: [[ref_discr:_.*]] = discriminant((*
// CHECK: switchInt(move [[ref_discr]]) -> [0: [[unreachable:bb.*]], 1: [[unreachable]], 2: bb5, 3: bb1, otherwise: [[unreachable]]];
match &plop.test3 {
Test3::A(_) => "A(Empty)",
Test3::B(_) => "B(Empty)",
Test3::C => "C",
Test3::D => "D",
};
// CHECK: [[discr:_.*]] = discriminant(
// CHECK: switchInt(move [[discr]]) -> [0: [[unreachable]], 1: [[unreachable]], 2: bb10, 3: bb7, otherwise: [[unreachable]]];
match plop.test3 {
Test3::A(_) => "A(Empty)",
Test3::B(_) => "B(Empty)",
Test3::C => "C",
Test3::D => "D",
};
// CHECK: [[unreachable]]: {
// CHECK-NEXT: unreachable;
}
fn main() {
simple();
custom_discriminant();
byref();
}
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